Flux Spellcasting

Here's a spellcasting method that lets wizards and other casters cast like there's no tomorrow. And if they keep slinging spells with wild abandon, there won't be.

An apprentice wizard, making a Big Mistake

Use the GLOG's levelless spells, Mishaps, and Dooms. Each day, you begin with 0 Flux Dice. Gain an FD after you cast a spell. When you cast a spell, [dice] equals your current Flux (if your Flux is 0, [dice] and [sum] is 1), to a maximum number of dice equal to level+1. Cantrips don't cause Flux and aren't affected by it. Some powerful spells require high Flux (or other conditions) to cast.

In the morning, prepare level+1 spells from your spellbook. These are the spells you can cast today. You can make an Intelligence check to swap one out during a short rest. Beat a 10 to do that the first time each day, then increase the threshold by 5 each time you successfully swap out a spell.

Flux decreases by 1 after taking a short rest, and to 0 after a long rest.

Casting Process
Step 1. Cast spell at current Flux (max dice is level+1); if Flux is 0, treat [dice] and [sum] as 1.
Step 2. Roll d6+Flux on the Flux Table.
Step 3. Gain 1 Flux.

Flux Table
1. Don't gain Flux.
2-3. Forget the spell you just cast until your Flux returns to 0.
4-6. Mishap.
7. Immediately cast another random spell you know, gaining Flux as normal.
8. Summon an Animate Spell of the spell you just cast. Spell level equals Flux.
9+. DOOM.

Here are some default Mishaps and Dooms if your casting class's aren't compatible with this system.

Mishaps
1. Fatigue for (Flux)d6 rounds, -Flux STR/DEX/CON
2. Take 2*Flux damage.
3. Arcane flare alerts everyone in area to you casting spell, target gets additional save to resist.
4. Turn into a random small mundane creature for (Flux)d6 rounds.
5. Spell targets something else at random.
6. Gain an additional Flux.

Dooms
First Doom. Lose the ability to cast spells for a day. Gain a spellscar.
Second Doom. Lose the ability to cast spells for a week. Gain a spellscar.
Final Doom. Magic Itself shows up, berates you, and takes away your magical powers forever.

Some of the theory behind this:

• If you're lucky, you can just keep casting Flux 0 spells by rolling 1 over and over again.
• I'm probably going to make cantrips more scarce if I fold this into a system, because the whole point of cantrips is to let casting classes do more in a system where they'll only be able to cast 1 or 2 spells a day; that doesn't apply here.
• You're going to get Mishaps more often with this system, and will take more short rests if you're careful. That being said, if you want to cast more than 1 spell per short rest, Flux will still accumulate.
• Rename Flux to something setting-appropriate for flavor. Right now I'm going for a generic arcane rift in the fabric of What Is Natural And Good In The World, but you can fluff it as slipping deeper under the influence of Magic Itself, or becoming increasingly inebriated under the influence of a thaumic narcotic, or any number of other escalating bad ideas.
• You can try to avoid Dooms by never going to 3 Flux, but if you roll 7s (the most magical of numbers, except perhaps 13 and 666), you might not have a choice. Such is the price you pay for cosmic power.